A thousand years before the birth of Christ, in an Andean valley in Peru, a priest may have handed a subject a ceremonial bowlful of the juice of the San Pedro cactus. That subject would then be led down into a black and confusing labyrinth. As the mescaline filtered through the body, shadows from some unseen light would have danced on the walls: maybe heads with snakes for hair, or heads with jaguar fangs. A sound that could be rushing water—or the snarl of panthers—may fill the air. Then comes another sound that would shake the subject’s skull like a rattle.

Terrified, he or she would do anything the priests say. Which would have been the point.

This is the theory of the acoustical madhouse of Chavín de Huántar, a 3,000-year-old temple complex about 150 miles north of Lima. This UNESCO World Heritage Site has seen its share of floppy-hatted archaeologists over the past century. But researchers today think they’re finding fresh answers to stubborn mysteries about how Chavín worked with the help of archaeoacoustics—an emerging field that pairs a 21st-century understanding of acoustics and musicology with ethnology and archaeology.

“If you have archaeology and no acoustics, you’re deaf,” says archaeoacoustician David Lubman. “And if you have acoustics and not the other, you’re blind. You need both” to understand ancient places like Chavín, he says.

In the last few years, practitioners in the field of archaeoacoustics have come up with intriguing (if sometimes controversial) new insights about well-trodden ground from Stonehenge to Chichén Itzá’s Mayan temples. The field’s showpiece, however, may be Chavín de Huántar, where researchers think that the original builders manipulated sound in surprisingly sophisticated ways.

Society around Chavín thrived in the Peruvian highlands for at least 2,000 years before the better-known Inca, but the people left no written language. What they did leave is the monumental stone temple complex with a maze of miles of passageways both underground and in buildings above ground. In both, strange acoustics are noticeable throughout.

In the 1970s archaeologist Luis Lumbreras proposed that a duct built into the complex was an “acoustic canal,” created so river water mimicked a thundering, feline rumble throughout the passages, called “galleries.” (Imagine an architectural organ that could be ‘played’ with help from many side ducts that transmit sound.) But for the most part archaeologists gave little thought to Chavín’s sounds.

Then in 2001 Stanford University archaeologist John Rick unearthed 20 decorated, well-worn conch-shell trumpets, or pututus, at the complex. They were clearly instruments, but what for? Rick returned in 2008 with researchers and microphones from Stanford’s Center for Computer Research in Music and Acoustics. The group found that sounds inside the galleries resonate at the same frequencies of the pututus and the same frequencies of typical male voices—sounds that are more prominent and drawn out. The sound of the conch-horn’s blow can rattle your eyeballs, as if it’s inside your head, Rick says. “It’s a deepness and a fullness and a reverberance.”

The funhouse effects don’t end there. In some passageways, there are barely any sounds—through a short duct you can see a person walking but can’t hear them. In others, sound disorients. “This environment is not only a physical maze, but it’s a sound maze,” says Miriam Kolar, a doctoral candidate who recently defended her dissertation on Chavín’s acoustics. “Experiments show that listeners standing in some areas of the dark galleries can wildly misidentify where sounds come from, but in other places, their perception is totally accurate,” she says Kolar. Whether or not the original builders intended to set up this sound-maze, “it’s a feature that can be used.”

Kolar has also discovered that the temple makers may have crafted another acoustic trick: making a stone oracle speak.

Deep in the labyrinth stands the Lanzón, a 15-foot stone statue; and nearby is a 15-foot-long duct, open to a sunken plaza outdoors. The duct is tapered, and, according to Kolar, is “an amazing filter for exactly the sound frequencies of the pututus,” a sort of megaphone built of stone that broadcasts the shell trumpet, while excluding other frequencies. And, the duct lines up perfectly with the idol’s mouth. Perhaps thousands of years ago a priest would blow a powerful note on the pututu, and the awestruck crowd outside would receive wisdom from the gods.

Why would people go to such effort—even reworking the galleries over 800 years, as evidence shows—to enhance these effects?

Rick has a theory: The complex appeared at the time the society was transforming from an egalitarian to a hierarchical society. “You have to make people believe that the changes that they’re going to undergo are natural,” says Rick. Chavín’s special effects—sound, and the evidence of psychedelic drugs such as mescaline, tricks of light, and (Rick guesses) even smoke and smells and costumes—were a shock-and-awe campaign by an emerging priesthood intent on humbling others into being followers, he believes.

“In general I’m cautious (not to say skeptical) about some of the specific claims made for archaeoacoustics,” says Chris Scarre, head of the Department of Archaeology at England’s Durham University and 2013 editor of the journal Antiquity, “but I find the arguments put forward for Chavín de Huántar fairly convincing.”

Kolar would like to further explore how the oracle’s “voice” worked, and study further how sounds made in Chavín’s galleries affect the brain to gain insight into how far sound manipulators innovated their way into initiates’ heads. A 2008 UCLA study, for instance, found that listening to a resonant frequency of 110 hertz (that of a low voice) temporarily shifted the activity in the brains of study volunteers’ brain activity (in areas involved in language, emotional processing, and decision making).

Maybe that offers a sound link to how people reacted during ancient ritual ceremonies.

A former reporter for the Seattle Times, Christopher Solomon writes frequently for the New York Times, Outside magazine and other publications, and his work has been anthologized inThe Best American Travel Writing. He can be found at www.chrissolomon.net.